An electronic entity such as a chip card containing time measurement elements includes a capacitative component (20) having a leak through the dielectric area thereof and being able to be charged when the entity is coupled to an electric power source and a member (22) for measuring the residual charge of the capacitative component which is implemented in a subsequent measure.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An electronic entity for carrying out transactions, comprising: at least one subsystem comprising a capacitive component having a dielectric space with a leak across the dielectric space; means for coupling said capacitive component to an electrical power supply so that the capacitive component is charged by said electrical power supply during a first transaction and for decoupling said capacitive component at the end of the transaction; and means for measuring a residual charge in said capacitive component during a new transaction, said residual charge being at least in part representative of a time elapsed since said first transaction, wherein fraud is detected by the time elapsed between said first transaction and said new transaction.
2. Electronic entity according to claim 1 , characterized in that the electronic entity comprises switching means for decoupling said capacitive component from said electrical power supply.
3. Electronic entity according to claim 2 , characterized in that said measuring means are used to determine an elapsed time.
4. Electronic entity according to claim 3 , characterized in that, said capacitive component being charged during a transaction, said measuring means are used during a transaction of this type to provide information at least partly representative of the time elapsed since the last transaction.
5. Electronic entity according to claim 1 , characterized in that the electronic entity is autonomous and in that said electrical power supply is external to the electronic entity.
6. Electronic entity according to claim 5 , characterized in that the electronic entity is a microcircuit card.
7. Electronic entity according to claim 1 , characterized in that said capacitive component ( 20 ) is a MOS technology capacitor whose dielectric space consists of silicon oxide.
8. Electronic entity according to claim 1 , characterized in that said measuring means comprise a field-effect transistor ( 30 ) whose gate is connected to a terminal of said capacitive component.
9. Electronic entity according to claim 8 , characterized in that said field-effect transistor is an MOS transistor, said gate ( 28 b ) floating during the time that elapses between two connections or couplings to an external power supply on the occasion of two successive transactions.
10. Electronic entity according to claim 9 , characterized in that said field-effect transistor comprises an insulative layer between the gate electrode and a substrate, said capacitive component comprises an insulative layer ( 24 ) forming the aforementioned dielectric space disposed between a plate ( 28 a ) and a substrate ( 26 ), and said plate and said gate electrode are connected together.
11. Electronic entity according to claim 10 , characterized in that the thickness of the insulative layer ( 34 ) of said transistor is substantially greater than the insulative layer ( 24 ) of said capacitive component.
12. Electronic entity according to claim 11 , characterized in that the thickness of said insulative layer of said transistor is approximately three times that of said capacitive component.
13. Electronic entity according to claim 11 , characterized in that the thickness of the insulative layer of said capacitive component is from 4 nanometers to 10 nanometers.
14. Electronic entity according to claim 8 , characterized in that said field-effect transistor is an MOS transistor, said gate ( 28 b ) floating during the time that elapses between two connections or couplings to an external power supply on the occasion of two successive transactions.
15. An electronic entity for carrying out transactions, comprising: at least two subsystems, each subsystem comprising a capacitive component having a dielectric space with a leak across the dielectric space, said leaks of said at least two subsystems being different; means for coupling said capacitive components to an electrical power supply so that said capacitive components are charged by said electrical power supply during a first transaction and for decoupling said capacitive components at the end of said first transaction; means for measuring a respective residual charge in each of said capacitive components during a new transaction, each of said respective residual charges in said capacitive components being at least in part representative of a time elapsed since said first transaction; and means for processing measurements of said respective residual charges to extract from said measurements information substantially independent of heat input to said electronic entity during the time elapsed between the two transactions.
16. Electronic entity according to claim 15 , characterized in that said processing means comprise a table of stored time values (T) addressed by said respective measurements.
17. Electronic entity according to claim 15 , characterized in that the electronic entity comprises a memory space defining said table.
18. Electronic entity according to claim 15 , characterized in that said processing means comprise software for calculating a predetermined function for determining said information as a function of said measurements and substantially independently of the heat input.
19. An electronic entity for carrying out transactions, comprising: an electrical power supply; a capacitive component having a dielectric space with a leak across the dielectric space; a connector, said connector couples said capacitive component to the electrical power supply so that the capacitive component is charged by said electrical power supply during a first transaction and for decoupling said capacitive component at the end of the transaction; and a field-effect transistor, said field-effect transistor measures a residual charge in said capacitive component during a new transaction, said residual charge being at least in part representative of a time elapsed since said first transaction, wherein fraud is detected by the time elapsed between said first transaction and said new transaction.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
March 24, 2003
October 7, 2008
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